Solid Gas Research Articles

Pendampingan Teknis Dalam Analisa Timbulan Limbah Medis Padat Pada Rumah Sakit SMS Berjaya Kabupaten Kolaka

Medical waste is produced in hospitals by a variety of means, including solid waste, gas, and liquid. Therefore, it is necessary to support the analysis of the production of solid medical waste at RS SMS Berjaya District of Kolaka. The purpose of this technical support is to find out the monthly quantity of solid medical waste as well as the solid medical waste disposal system carried out at SMS Berjaya Hospital. Use both qualitative and quantitative descriptions. The accompanying results showed that the solid medical waste produced from medical activities in each room during the observation was a source of non-acute infectious garbage. Class II and III hospital facilities produce the highest percentage of medical garbage 23.13 kg/day (46.26%), and the smallest unit of medical waste in each room is 2.59 kg/ day (5.18%). And in the Infectious Object Garbage, the largest in Class II & III facilities is 1.32 kg/day (29,53%). And Nifas/Perinatology facilities are much smaller than 0.4kg/day (8.95%). SMS Berjaya Hospital has a solid, well-implemented medical waste management system.

Surgical Technique for Sphinkeeper® Implantation.

Fecal incontinence is a distressing condition characterized by the involuntary loss of solid and liquid stool and gas, It affects a significant proportion of the general population, with a reported prevalence ranging from 1% to 20%. Despite its considerable impact on quality of life, therapeutic options for fecal incontinence remain limited. Current treatment modalities for fecal incontinence include conservative approaches such as dietary modifications, pelvic floor exercises, and pharmacotherapy. Surgical interventions, including sphincteroplasty or sacral nerve stimulation, may be considered in more severe cases. Recently, THD Labs (THD S.p.A. Correggio (RE), Italy) introduced the Gatekeeper® as a novel device that supports the implantation of up to four solid prostheses into the intersphincteric groove. Early data were promising, with success rates above 50% and only a few perioperative complications. Subsequently, Gatekeeper® was modified by increasing the length and number (up to 10) of prostheses, and renamed Sphinkeeper® (THD). With this device, nine to 10 small incisions measuring 2 mm are made at a distance of 2-3 cm from the anus. The intersphincteric space is accessed using the delivery system, and positioning is verified through endoanal ultrasound. This procedure is repeated for all 10 prostheses placed around the entire circumference. The Sphinkeeper® offers the potential to improve the management of fecal incontinence, and offers patients a less-invasive alternative to traditional surgical approaches.

Data driven reduced modeling for fluidized bed with immersed tubes based on PCA and Bi-LSTM neural networks

The fast and accurate reduced-order modeling of fluidized beds is a challenging task in the field of fluid dynamics, owing to their high dimensionality and nonlinear dynamic behavior. In this study, a nonintrusive reduced order modeling method, the reduced order model based on principal component analysis and bidirectional long short-term memory networks (PBLSTM ROM), was developed to capture complex spatio-temporal dynamics of fluidized beds. By combining principal component analysis and Bidirectional long- short-term memory networks, the PBLSTM ROM effectively extracted dynamic evolution information without any prior knowledge of governing equations, enabling reduced-order modeling of unsteady flow fields. The PBLSTM ROM was validated using the solid volume fraction and gas velocity flow fields of a fluidized bed with immersed tubes, showing superior performance over both the PLSTM and PANN ROMs in accurately capturing temporal changes in the fluidization fields, especially in the region near immersed tubes where severe fluctuations appear. Moreover, the PBLSTM ROM improved the simulation speed by five orders of magnitude compared to traditional computational fluid dynamics simulations. These findings suggest that the PBLSTM ROM presents a promising approach for analyzing the complex fluid flows in engineering practice.

Anisotropic continuum framework of coupled gas flow – adsorption – deformation in sedimentary rocks

AbstractSolid deformation is always a crucial factor of gas transport in sedimentary rocks. While previous studies always adopt the assumption of isotropic poroelastic deformation, anisotropic poroelastoplastic deformation is rarely considered, despite anisotropy being a ubiquitous property of natural sedimentary rocks. In this work, an anisotropic poromechanical model is established to analyze the matrix porosity and apparent permeability evolutions during the process of gas migration. Using a thermodynamic formulation that treats the fluid–solid interface as an independent phase, we derive a rate form for matrix porosity and obtain the new dissipation function that contains three parts: dissipations from solid deformation, gas adsorption, and fluid flow. For gas adsorption, we justify the rationality of the adopted model; for fluid flow, the updated porosity can be substituted into sophisticated apparent permeability models for full‐scale analysis; and for solid deformation, a recently developed constitutive model appropriate for rocks exhibiting transverse isotropy in both the elastic and plastic responses is adopted in this work. Through the novel stress‐point simulation incorporating two effective stress measures and adsorption strain, new patterns of apparent permeability are obtained, which fit the experimental data quite well and cannot be reproduced from the assumption of isotropic poroelasticity. The advantages of our poromechanical model include thermodynamic consistency and the ability to employ finite‐element‐based formulation. Finally, an initial‐boundary value problem of gas production considering anisotropic plasticity is conducted, and the effects of the bedding plane and different adsorption models are highlighted.

A numerical study on autoignition of finite thick polymethyl methacrylate (PMMA) subjected to thermal radiation and forced airflow

A 2D numerical model coupling condensed and gas phases is developed to investigate autoignition of finite thick PMMA heated by radiation in forced airflow. Six sample thicknesses (1–15 mm), four heat fluxes (30–60 kW/m2), and five airflow velocities (0–1.2 m/s) are considered to examine their effects. The model is first verified by measured surface temperatures in experiments. Then three boundary layers (BL), velocity, thermal and concentration BLs, are studied based on simulation results and BL theory. BL thickness, local and surface-averaged frication coefficients, convective heat and mass transfer coefficients at solid–gas interface are estimated and compared with analytical results. Meanwhile, Damköhler numbers (Da) in non-ignition cases are calculated to reveal their impact. The results show that the model predicts measured surface temperatures well despite some divergence for thin samples due to deformation. Simulated velocities and thermal BL thicknesses agree well with analytical ones, yielding a maximum error of 33 % for concentration BL. Numerical convective heat and mass transfer coefficients match analytical ones well, whereas large discrepancy exists for friction coefficient. Two types of Da evolution, corresponding to different controlling mechanisms of non-ignition cases, separated by 6 mm sample are identified.

Salting out of americium-241 in the sorption process using a solid-phase extractant based on TODGA

Today, the «Proryv» project is developing effective methods of reprocessing irradiated nuclear fuel (SNF) to return long-lived radionuclides to the fuel cycle to close it. One of the challenges of closed fuel cycle development is the reprocessing of highly active nitric acid raffinates from the PUREX-process. To achieve this task, it is necessary to separate americium-241 from liquid radioactive waste. When processing and fractionating liquid radioactive waste, extraction and sorption technologies for the extraction, purification and concentration of radionuclides are widely used. The highest efficiency and selectivity in the extraction processes of actinoids (III) and lanthanides (III) with rare earth elements (REE) and transplutonium elements (TPE) from nitric acid solutions of spent nuclear materials reprocessing were shown by extractants based on N, N, N', N'-tetraoctyldiglycolamide (TODGA). Before using a solid-phase extractant based on TOGDA, the ions of the substance in solution must be converted to neutral complexes or other non-dissociated compounds. This can be achieved by adding neutral salts to the solution, which reduce the solubility of the elements to be separated, shift the extraction distribution and significantly increase the extraction efficiency. The extracted substance is extracted in the form of a new phase - solid precipitate, liquid or gas phase, and in the case of liquid extraction there is an increase in the capacity of the extractant for the target component. Therefore, the addition of salts-salting agents to the aqueous phase to increase the ionic strength of the solution increases the distribution coefficients of extracted substances, which in turn increases the capacity of sorbents. The purpose of this work is to study the process of salting out of americium-241 during sorption using an experimental modified sample of solid-phase extractant based on TODGA in the studied model solutions of liquid radioactive waste with a uranium macrocomponent for different NaNO3 contents. The study revealed that the highest distribution coefficients for the sorption of americium-241 and uranium were obtained in a solution containing 100 g/l NaNO3, but for uranium this effect is much less pronounced than for americium-241. During the study of the sorption kinetics of americium-241 and uranium, the salting effect was revealed, which is confirmed by the values of the equilibrium concentrations of americium-241 and uranium in solution at the same time point but with different NaNO3 concentrations. The difference in the equilibrium concentrations for americium-241 was an order of magnitude towards its decrease when NaNO3 concentration was increased up to 100 g/litre. The use of this effect makes it possible to obtain the maximum capacity for americium-241 in the system with uranium macrocomponents

Experimental investigation of sorted municipal solid wastes producer gas composition in an updraft fixed bed gasifier

Three kinds of municipal solid waste (MSW) from mechanical biological treatment plants, i.e., Fraction after Drum Separator (FDS), Solid Recovered Fuel (SRF) and Plastic Packaging Mixture (PPM), were investigated. These samples were gasified in fixed-bed updraft gasifier under allothermal (800 °C) air supply conditions. Two different air equivalence ratios (ER), i.e., 0.15 ± 0.02 and 0.21 ± 0.04 were created to determine the influence on MSW producer gas properties. Derivative thermogravimetry analysis shows the same volatile release temperatures (330 °C, 500 °C) for all tested MSW kinds. Chromatography analysis of MSW producer gas revealed that the reduction of ER from 0.21 to 0.15 increase the heating value of combustible gases. PPM producer gas contains the highest H2 content – 11.39 %. The highest tar content (47.44 g/m3) was measured in SRF producer gas and primarily consisted of benzene, toluene, naphthalene, and acenaphthylene. The results of the sorted MSW gasification experiments show that the allothermal updraft fixed-bed gasifier is suitable for the production of producer gas that can be used in gas engines.

Validation of the single-event method for low-energy electron transport via stopping power calculations with MCNP

Monte Carlo simulations of low-energy (<50 keV) electron transport in matter are essential for a broad range of application fields. Several Monte Carlo codes have developed specialized treatments for this case, but a comprehensive validation of low-energy electron transport for general-purpose simulations remains lacking in the literature. One approach to accomplish this validation is calculation of stopping power using low-energy electron transport physics, as stopping power is a fundamental radiation transport quantity which must be simulated accurately for nearly any application. In this work, we use the Monte Carlo N-Particle (MCNP) radiation transport code with the single-event method for electron transport to calculate stopping powers of low-energy electrons (50 eV to 30 keV) in 41 elemental solids, 14 compound solids, and five rare gas solids, comparing simulation results to published semi-empirical stopping power calculations from optical measurements. In general, the simulations give good agreement (typically within ±10%) with semi-empirical stopping power values at higher energies: 300 eV and above for most elemental solids, 1 keV and above for compound solids, and 400 eV and above for rare gas solids. Agreement between MCNP and semi-empirical values is worse below these energies. The most significant source of error is the EPRDATA14 cross section data, which does not account for changes in electronic structure due to solid-state bonding, particularly in compound materials. The simplistic model of atomic excitation used to generate the EPRDATA14 cross sections is another key source of error. Additionally, the breakdown of the continuous slowing-down approximation introduces significant uncertainty at low energies, although this is a limitation of the calculation method and not of the simulation procedure. Accounting for these and other uncertainty sources, the single event method in MCNP is robust and able to give good accuracy for a variety of low-energy electron transport problems through diverse kinds of materials.

Research progress on moisture resistance of gas sensors

AbstractSensors used to detect explosive, flammable, toxic, and harmful gases are in focus of research. The gas sensor can be affected by many factors in the process of use, and among the many adverse elements affecting the function of the gas sensor, humidity is the most common. With the rapid development of gas sensors, the influence of humidity on gas sensors has been paid more and more attention. To reduce the impact of humidity, many methods have been proposed. In this review, the specific impact of humidity on the function of metal‐oxide semiconductors and solid electrolyte gas sensors is summarized. Practical techniques are proposed to reduce the effect of humidity on device performance, which is of great help in improving the detection efficiency and quality of gas sensors in high‐humidity environment. The information may be valuable for expanding the application field of gas sensors.

Production efficiency and safety assessment of the solid waste-derived liquid hydrocarbons

Global fossil resource utilisation remains a concern. Organic fuels and chemicals produced through catalytic synthesis out of biomass/waste feedstock can help reduce the share of fossil resource utilisation.In this study, a solid waste-derived producer gas from the cross/updraft sliding bed gasification process was applied in a fixed bed catalytic reactor with the goal of producing rich hydrocarbon chains. The specific producer gas with CO = 10%vol., H2 = 9%vol. and CH4 = 4%vol. was applied into the catalytic reactor along with catalysts Cat-Co or Cat-CoMnK at 15 bar pressure. Both catalysts were investigated in temperature regimes of 250, 280 and 310 °C, and the liquefaction number and hydrocarbon production were determined. The liquid products were qualitatively analysed afterwards, and the safety assessment, comprising the autoignition test, was performed. The obtained results defined an optimal operating temperature close to 280 °C a value for both catalysts. The individual hydrocarbon compounds were defined mostly by alkanes and alkenes of C10–C14 hydrocarbon groups in the case of both applied catalysts. The application of MnK-promoted catalyst resulted in the production of a significant amount of C6 hydrocarbon groups as well. The results point out a wide range of compounds utilisable in many different applications throughout the production sphere and suggest the possibility of autothermal air gasification of solid recovered fuel with the goal of producing gas for catalytic synthesis with reduced operation costs. From the safety point of view, the temperature of 227.7 °C was defined as the lowest value when autoignition occurs. This lowest temperature is relevant to the Cat-Co 280 °C synthesis scenario.

High resolution spectroscopy of thulium atoms implanted in solid noble gas crystals

High resolution spectroscopy of thulium atoms implanted in solid noble gas crystals

Biochar production from the pyrolysis of food waste: Characterization and implications for its use

Food waste (FW) represents a large group of wastes that impose several issues on their management, especially in terms of microbiological and leaching pollution, and greenhouse gas emissions. According to the EU circular economy vision, finding a new way for FW valorisation to obtain reusable materials or compounds represents a priority. Thermal treatment represents one of the suitable ways for FW processing, and pyrolysis in particular presents many advantages in producing solid carbonaceous biochar, reusable oil and gas. This paper analyses biochar that was produced via thermal pyrolysis of FW. The influence of an organic additive (wooden sawdust) and a catalyst (zeolite) on the pyrolytic process at 600 °C was investigated. The results highlight how the initial composition of the feedstock (FS) influenced the characteristics of the obtained biochar. The addition of organic additives and catalyst did not change significantly the Brunauer–Emmett–Teller surface area and the calorific value. For all the analysed parameters, all tested FS respected the guidelines proposed by International Biochar Initiative (IBI) and the European Biochar Certificate (EBC) for possible reuse in agriculture and urban areas. The results suggest that biochar from FW could be potentially used in agriculture and urban green infrastructure, but the authors suggest further studies, especially on the effect of high electrical conductivity due to the typical high concentration of salts in FW.

Consideration on Accuracy of Numerical Analysis of Solid–Gas Two-Phase Flow with Reaction Using Energy Conservation Equation with Temperature as a Variable

Consideration on Accuracy of Numerical Analysis of Solid–Gas Two-Phase Flow with Reaction Using Energy Conservation Equation with Temperature as a Variable

Determination of Lorazepam and Diazepam Using Modified Nanocrystalline Cellulose for Ultrasonic-Assisted Dispersive Solid Phase Microextraction (UA-DSPME) and Gas Chromatography-Mass Spectrometry (GC-MS)

A rapid and effective method utilizing ultrasonic assisted-dispersive solid-phase microextraction coupled with gas chromatography/mass spectrometry (GC/MS) was developed for the determination of lorazepam and diazepam in biological and aqueous samples. A modified nanocrystalline cellulose-based sorbent was prepared and applied for the microextraction of the analytes. The extraction efficiency of the sorbents prepared using self-assembled N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, including cellulose nanostructure and modified nanocrystalline cellulose, was compared. The modified cellulose nanostructure was characterized using thermogravimetric analysis (TGA), energy dispersive X-ray (EDX), and Fourier transform infrared spectroscopy (FTIR). Additionally, the study investigated the effects of relevant factors on the extraction/desorption performance, including extraction time, ionic strength, and the type and volume of the desorption solvent. The method achieved limits of detection of 1 ng mL−1 and 3 ng mL−1 and quantification limits of 4 ng mL−1 and 10 ng mL−1 for lorazepam and diazepam, respectively. Furthermore, the developed method demonstrated good repeatability with relative standard deviations of 4% and 6% (n = 5) for the spiked analyte aqueous solutions at 50 ng mL−1. The method also exhibited high linearity (R > 0.9996) in the range from 10 to 1000 ng mL−1.

Effect of electron beam irradiation on surface molecule and flashover voltage of epoxy composites

AbstractThe unsatisfactory insulating properties of solid–gas interfaces seriously restrict the development of high‐voltage electrical equipment and threaten their power supply stability. Electron‐beam irradiation (EBI) can effectively improve the surface flashover voltage of dielectrics. However, the underlying mechanism of EBI in tailoring the surface trap and improving the flashover voltage remains unclear. In this study, the surface morphologies and chemical compositions of epoxy composites treated with EBI were investigated. In addition, the surface wetting properties, surface charge migration parameters, and surface flashover voltages were experimentally characterised. It was found that EBI aggravated the surface morphology, changed the surface chemical components, and repressed surface charge transportation. As a result, the contact angle was reduced from 103.7° to 78.43°, and the flashover voltage in SF6 was increased from 35.26 to 38.90 kV. DFT calculations showed that the newly generated C–O–H and C=O bonds on the surface molecules after EBI formed charge centres at the molecular electrostatic potential, which enhanced the trapping effect of the surface deep trap. As a result, surface charge migration was repressed, and the surface flashover voltage was improved. This study could promote the further development of EBI on materials modification.

Oxygen vacancy-engineered BiOCl nanoflake with silver decoration for enhanced photocatalytic CO2 reduction at solid-gas interface

Photocatalytic conversion of CO2 into valuable chemicals is an attractive way to mitigate the greenhouse effect. However, the poor mass transfer of CO2 in a liquid-phase reaction limits its conversion rate and carbon product selectivity. Here, we developed a gas-phase photocatalytic CO2 reduction by Ag/BiOCl-oxygen vacancy nanoflakes (Ag/BiOCl-OV NFs) where the catalytic reaction occurs at the solid–gas interface between Ag/BiOCl-OV and CO2/vapor reactants. Such a solid–gas system allows rapid adsorption/desorption of CO2 on the surface of photocatalysts, enhanced light absorption and electron-hole separation, resulting in promoted photocatalytic reaction rate and CO selectivity compared to the solid–liquid systems. By supporting Ag/BiOCl-OV NFs on a photothermal substrate that has broadband light absorption to perform local heating for in-situ photothermal enhanced photocatalytic reaction. The synergistic effect of Ag nanoparticles, OVs and photothermal, the highly-selective CO product shows an evolution rate of 76 μmol g-1h−1, 17.6 times higher than that of pure BiOCl NFs.

Processing plastic waste via pyrolysis-thermolysis into hydrogen and solid carbon additive to ethylene-vinyl acetate foam for cushioning applications

A strategy for enhancing value creation from pyrolysis gas and oil, derived from plastic waste, through the generation of two additional outputs of solid carbon and hydrogen was investigated. Three types of hard-to-recycle plastic waste (marine plastic litter, household mixed plastics and cosmetic products packaging) were thermally treated in two stages: (i) decomposition of feedstock into gas and oil via pyrolysis at 600 °C; and (ii) thermolytic conversion of the pyrolysis gas and a fraction of oil into hydrogen and solid carbon at 1300 °C separately. The thermolysis of both pyrolysis gas and oil fractions predominantly resulted in the production of solid carbon (39–70 wt% per plastic feedstock and carbon content of 91.3–98.6 wt%) and H2-rich gas (H2 yield of 5.9–10.8 wt% per plastic waste feedstock and H2 content of 71.4–97.2 vol% per gas volume). The incorporation of pyrolysis oil into the thermolysis process could enhance the outputs of solid carbon and hydrogen. Characterizations of solid carbon and hydrogen obtained from pyrolysis gas and oil fractions were further conducted. The observed similar properties of H2 and solid carbon from pyrolysis gas and oil supported the feasibility of introducing all the pyrolytic products together into the thermolysis process without condensation of oil. To enhance the value of these solid carbon derived from plastics for practical usage, we utilized the obtained solid carbon as a reinforcing agent for polymer composite foam development. The solid carbon reinforced composite foam displayed great abrasion resistance (wear loss: 240 mg), compression strength (0.347 MPa), and dynamic impact properties (energy returned: 124 J/m and energy absorbed: 57.3 J/m), emphasizing the viability of solid carbon as a nucleating agent and reinforcing filler in polymer foam for cushioning applications. Overall, the strategy of pyrolysis-thermolysis, which harnesses both pyrolysis gas and oil, unlocks additional value creation by producing two new outputs from plastic waste. Depending on the market prices for solid carbon and hydrogen, this can substantially change the economics of plastic waste management and create new revenue streams, incentivizing plastic waste collection and processing.

Novel high intrinsic permittivity in new perovskite ceramic GdCa2Cu3Oδ

In the present work, the GdCa2Cu3Oδ (GdCCO) compound was prepared using the conventional solid-state reaction tool, and their crystal structures and dielectric properties were systematically studied. X-ray diffraction analysis and Rietveld refinement results confirmed that GdCCO perovskite crystallizes in the tetragonal structure with the P4/mmm space group. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) analysis confirm the decomposition of CaCO3 into calcium oxide (CaO) solid and carbon dioxide (CO2) gas at 800 °C. The composition of the grains was qualitatively examined using the EDX system attached to scanning electron microscopy (SEM). The XPS analysis was performed to investigate the oxidation state of the GdCCO perovskite elements. The frequency and temperature dependences of the complex impedance spectra and the dielectric responses of the compound GdCCO synthesized have been investigated. We first observed two semicircles conforming to grain and grain boundary responses in the impedance plots. Further, than the ambient temperature, the magnitude of the permittivity from the grain boundary (εr′ = 104 and C = 10−11 F) remains constant over most of the frequency range but decreases rapidly in the MHz frequency region. The temperature dependences of the dielectric responses show the excellent temperature stability of ε′ (Δε′=±15%), a wide temperature side (-30 – 125 °C), and higher performance of characteristics (giant ε′ 104 and low dielectric loss). These excellent performances confirmed that the prepared ceramic reveals a potential application for high-temperature Y5R and Y6R capacitors.

Dimethyl sulphide: The oyster-like odourant of Mertensia maritima

The oyster plant (Britain) or oyster leaf (North America), Mertensia maritima (L.) Gray has a strong oyster-like odour. Headspace volatiles from fresh crushed leaves of this plant were analysed using solid phase microextraction (SPME) and gas chromatography– mass spectrometry (GC–MS). Dimethyl sulphide was detected emanating from the crushed leaves, a compound that is noted for being a major part of the odour profile of raw oysters.

Simulation study on a novel solid–gas coupling hydrogen storage method for photovoltaic hydrogen production systems

Compressed hydrogen storage in photovoltaic hydrogen production systems faces several challenges, including limitations in storage volume, compression energy consumption and safety concerns. To improve the comprehensive hydrogen storage performance, this study develops a novel solid–gas coupling hydrogen storage method that combines metal hydride and phase change material (MH-PCM). Firstly, a vertical MH-PCM solid storage model considering the natural convection effect is proposed and investigated. Building upon this model, the solid–gas coupling hydrogen storage is constructed and integrated into the photovoltaic hydrogen production system to evaluate its comprehensive storage performance. Results reveal that considering natural convection leads to an approximately 12.7 % increase in the average storage rate, but is also accompanied by an uneven storage process. To address this unevenness and further enhance the storage rate, it's advisable to focus on structural optimization at the bottom of the tank. Additionally, improving the PCM thermal conductivity and hydrogen inlet pressure (to approximately 1 MPa) are also proven effective strategies. The proposed solid–gas coupling hydrogen storage demonstrates comprehensive advantages, particularly compact size and reduced energy consumption. Furthermore, appropriately increasing the coupling ratio between solid and gaseous capacities can achieve the even smaller storage volume. These findings can provide valuable theoretical and engineering guidance for implementing such hydrogen production and storage systems.